//<p>给你一个整数 <code>n</code> ，求恰由 <code>n</code> 个节点组成且节点值从 <code>1</code> 到 <code>n</code> 互不相同的 <strong>二叉搜索树</strong> 有多少种？返回满足题意的二叉搜索树的种数。</p>
//
//<p> </p>
//
//<p><strong>示例 1：</strong></p>
//<img alt="" src="https://assets.leetcode.com/uploads/2021/01/18/uniquebstn3.jpg" style="width: 600px; height: 148px;" />
//<pre>
//<strong>输入：</strong>n = 3
//<strong>输出：</strong>5
//</pre>
//
//<p><strong>示例 2：</strong></p>
//
//<pre>
//<strong>输入：</strong>n = 1
//<strong>输出：</strong>1
//</pre>
//
//<p> </p>
//
//<p><strong>提示：</strong></p>
//
//<ul>
//	<li><code>1 <= n <= 19</code></li>
//</ul>
//<div><div>Related Topics</div><div><li>树</li><li>二叉搜索树</li><li>数学</li><li>动态规划</li><li>二叉树</li></div></div><br><div><li>👍 1800</li><li>👎 0</li></div>

package com.rising.leetcode.editor.cn;

/**
 * 不同的二叉搜索树
 * @author DY Rising
 * @date 2022-06-15 19:45:53
 */
public class P96_UniqueBinarySearchTrees{
    public static void main(String[] args) {
        //测试代码
        Solution solution = new P96_UniqueBinarySearchTrees().new Solution();
        System.out.println(solution.numTrees(4));
    }
	 
//力扣代码
//leetcode submit region begin(Prohibit modification and deletion)
class Solution {
    public int numTrees(int n) {
        int[] G = new int[n + 1];
        G[0] = 1;
        G[1] = 1;

        for (int i = 2; i <= n; ++i) {
            for (int j = 1; j <= i; ++j) {
                G[i] += G[j - 1] * G[i - j];
            }
        }
        return G[n];
    }
}

//leetcode submit region end(Prohibit modification and deletion)

}
